Question: Q. 15. Give reasons for the following :
(i) A photodiode, when used as a detector of optical signals is operated under reverse bias.
(ii) The band gap of the semiconductor used for fabrication of visible LED’s must at least be
A&E [CBSE SQP 2014]
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Solution:
Ans. (i) When operated under reverse bias, the photodiode can detect the changes in current with the changes in light intensity more easily.
(ii) The photon energy, of visible light photons varies from about
[CBSE Marking Scheme 2014] 1½
Long Answer Type Questions
(5 marks each)
